21222111221 has 8 divisors (see below), whose sum is σ = 21526760640. Its totient is φ = 20918627712.

The previous prime is 21222111203. The next prime is 21222111227. The reversal of 21222111221 is 12211122212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21222111221 - 2²² = 21217916917 is a prime.

It is a super-2 number, since 2×21222111221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21222111221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222111227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 254780 + ... + 327653.

It is an arithmetic number, because the mean of its divisors is an integer number (2690845080).

Almost surely, 2^21222111221 is an apocalyptic number.

It is an amenable number.

21222111221 is a deficient number, since it is larger than the sum of its proper divisors (304649419).

21222111221 is an equidigital number, since it uses as much as digits as its factorization.

21222111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 582955.

The product of its digits is 64, while the sum is 17.

Adding to 21222111221 its reverse (12211122212), we get a palindrome (33433233433).

The spelling of 21222111221 in words is "twenty-one billion, two hundred twenty-two million, one hundred eleven thousand, two hundred twenty-one".